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o Add pmap lock around pmap_fault_fixup() to ensure other thread will not

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modify l3 pte after we loaded old value and before we stored new value.
o Preset A(accessed), D(dirty) bits for kernel mappings.

Reported by:	kib
Reviewed by:	markj
Discussed with:	jhb
Sponsored by:	DARPA, AFRL
This commit is contained in:
br 2018-10-26 12:27:07 +00:00
parent 1f5206e35e
commit 6033ae7fa3
1 changed files with 15 additions and 4 deletions
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19
sys/riscv/riscv/pmap.c
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@ -2015,16 +2015,21 @@ pmap_fault_fixup(pmap_t pmap, vm_offset_t va, vm_prot_t prot)
pt_entry_t orig_l3;
pt_entry_t new_l3;
pt_entry_t *l3;
int rv;
rv = 0;
PMAP_LOCK(pmap);
l3 = pmap_l3(pmap, va);
if (l3 == NULL)
return (0);
goto done;
orig_l3 = pmap_load(l3);
if ((orig_l3 & PTE_V) == 0 ||
((prot & VM_PROT_WRITE) != 0 && (orig_l3 & PTE_W) == 0) ||
((prot & VM_PROT_READ) != 0 && (orig_l3 & PTE_R) == 0))
return (0);
goto done;
new_l3 = orig_l3 | PTE_A;
if ((prot & VM_PROT_WRITE) != 0)
@ -2033,7 +2038,8 @@ pmap_fault_fixup(pmap_t pmap, vm_offset_t va, vm_prot_t prot)
if (orig_l3 != new_l3) {
pmap_load_store(l3, new_l3);
pmap_invalidate_page(pmap, va);
return (1);
rv = 1;
goto done;
}
/*
@ -2041,7 +2047,10 @@ pmap_fault_fixup(pmap_t pmap, vm_offset_t va, vm_prot_t prot)
* the PTE shouldn't have resulted in a fault.
*/
return (0);
done:
PMAP_UNLOCK(pmap);
return (rv);
}
/*
@ -2084,6 +2093,8 @@ pmap_enter(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot,
new_l3 |= PTE_W;
if ((va >> 63) == 0)
new_l3 |= PTE_U;
else
new_l3 |= PTE_A | PTE_D;
new_l3 |= (pn << PTE_PPN0_S);
if ((flags & PMAP_ENTER_WIRED) != 0)